Synthetic routes to prototype macrocyclic, bicyclic, and spirocyclic units present in the novel macrocyclic tetronic acid antitumor antibiotic, kijanimicin, will be examined. The aglycone kijanolide is the initial target of this project. Particular attention will be accorded to the tetronic acid substructure and the macrocyclic ring of the aglycon. The synthetic methods developed here will have general utility in the synthesis of other complex carbocyclic substances, including chlorothricolide and tetrocarin-A. The individual units and their combinations represent novel structures with potential biological activity in the antitumor and antibiotic areas. Kijanimicin shows activity against anaerobic bacteria and acts as an antimalarial in mice. Tetrocarin-A, a close analog of kijanimicin, suppresses RNA synthesis in B. subtilis and inhibits growth of experimental sarcoma 180 and leukemia P338 tumors in mice.